C++ - lesson 6 | HackIndia Skills

C++ - lesson 6 | HackIndia Skills | HackIndia

#include <iostream>
#include <string>
#include <utility>

int main() {
    std::string a = "HackIndia C++ project";

    std::string b = a;              // copy: a still has the text
    std::string c = std::move(a);   // move: c takes a's contents if possible

    std::cout << "b = " << b << '\n';
    std::cout << "c = " << c << '\n';

    a = "new value";               // OK: reuse after assigning a fresh value
    std::cout << "a = " << a << '\n';
}

Example

A project-style use

Suppose your project reads tasks from input and stores them. If you build a Task object locally and then store it, move it when you are done with the local object.

#include <string>
#include <vector>
#include <utility>

struct Task {
    std::string title;
    std::string owner;
};

int main() {
    std::vector<Task> backlog;

    Task t{"Fix login bug", "Asha"};
    backlog.push_back(std::move(t));   // t is no longer needed here

    // Do not read t.title here expecting "Fix login bug".
}

Understand move semantics plainly

One idea

Why moves matter

Copy versus move

What std::move does

Do not overuse it

A project-style use

Prefer simple ownership

Do this now

Quick check